NEW YORK (Reuters Health) - Magnetic resonance (MR) elastography noninvasively provides a quantitative assessment of liver fibrosis, according to new research findings.

"Conventional imaging modalities such as CT, MRI, and ultrasonography are not capable of demonstrating liver fibrosis prior to the onset of cirrhosis," Dr. Richard L. Ehman from Mayo Clinic, Rochester, Minnesota told Reuters Health. "The availability of a reliable, noninvasive method for detecting liver fibrosis could have a substantial impact on the management of patients with chronic liver disease."

Dr. Ehman and colleagues developed a method for measuring liver stiffness with MR elastography and prospectively tested the technique on 12 healthy volunteers and on 12 patients with liver fibrosis.

The mean liver stiffness in healthy volunteers was 2.0 kPa, the authors report in the August issue of Radiology, with no significant difference between subcostal and transcostal images, whether they were orthogonal or oblique.

Among the patients with chronic liver disease who underwent liver biopsy, one had no detectable fibrosis, four had stage 1 liver fibrosis, three had stage 2 fibrosis, three had stage 3 fibrosis, and one had stage 4 fibrosis.

The liver stiffness in the patient without fibrosis was 2.7 kPa, the researchers note, compared with a mean liver shear stiffness of 5.6 kPa among the 11 patients with varying degrees of liver disease.

Since this study was completed, "we have substantially improved the technology, especially in the way that mechanical waves are applied to the liver," Dr. Ehman said. "As a result, we are now able to generate cross-sectional maps of the elasticity of the entire liver in a very brief acquisition time."

"We have expanded our clinical trial with the technique, using the improved methods," Dr. Ehman explained. "Shortly, we will have enough additional data, together with biopsy results, to be able to report the sensitivity and specificity of MR elastography for diagnosing liver fibrosis in this larger series."